Moq setup method failing on callback-CodePudding

My unit test is failing on setup method

var myMock = new Mock<IMyInterface<IImportLine>>();
        myMock.Setup(m => m.StartExecution(It.IsAny<Func<Stream, IMyInterface<IImportLine>, bool>>(), null))
                     .Callback<Func<Stream, IMyInterface<IImportLine>, bool>>(action => action(null, new IMyInterface<IImportLine>()));

IMyInterface looks like below

public interface IImportTransport<T> where T : IImportLine
{
    void StartExecution(Func<Stream, ImportOperation<T>, bool> processor, string id = null);
}

The error message is System.ArgumentException : Invalid callback. Setup on method with parameters (Func3,String) cannot invoke callback with parameters (Func3).

How do we fix this?

CodePudding user response：

You need to provide an argument to your callback that corresponds to the id parameter (even though you know it'll be null).

var myMock = new Mock<IMyInterface<IImportLine>>();
myMock.Setup(m => m.StartExecution(It.IsAny<Func<Stream, IMyInterface<IImportLine>, bool>>(), null))
     .Callback<Func<Stream, IMyInterface<IImportLine>, bool>>(
         (action, id) => action(null, new IMyInterface<IImportLine>()));

Since you aren't using that parameter, you can use a discard if you like.

var myMock = new Mock<IMyInterface<IImportLine>>();
myMock.Setup(m => m.StartExecution(It.IsAny<Func<Stream, IMyInterface<IImportLine>, bool>>(), null))
     .Callback<Func<Stream, IMyInterface<IImportLine>, bool>>(
         (action, _) => action(null, new IMyInterface<IImportLine>()));